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Finding the Fourth Proportional to 86.26, 128.66 and 79.88

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Solution

The fourth proportional to 86.26, 128.66 and 79.88 is: 119.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.26 : 128.66 = 79.88 : x
  2. Step 2: Convert to fraction form
    86.26/128.66 = 79.88/x
  3. Step 3: Cross multiply
    86.26x = 128.66 × 79.88
  4. Step 4: Simplify right side
    86.26x = 10,277.28
  5. Step 5: Solve for x
    x = 10,277.28/86.26
  6. Step 6: Final answer
    x = 119.15

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.